1. Field of the Invention
The present invention relates to an alkaline dry cell having an excellent performance, suitable for the recent super heavy load or a heavy load application.
2. Description of the Related Art
Recently, super heavy load discharge or a heavy load application, such as portable AV devices including personal digital assistants (PDA), CD players, MD players and liquid crystal television sets, and portable telephones has been required for an alkaline dry cell. However, conventional positive electrode cell cases of alkaline dry cells are produced by drawing a steel sheet preliminarily applied with nickel-plating on both sides, or by drawing a steel sheet and then applying nickel-plating on it.
Since the former process comprising of drawing a steel sheet preliminarily applied with nickel-plate generates cracks on the nickel-plating surface to expose the iron base, the contact resistance rises therefor The latter process comprising of drawing a steel plate and then applying nickel-plating involves a problem in that the inner surface of the cell case is poorly applied with nickel-plating although the outer surface is well applied with the nickel-plating. For example, when nickel-plating is applied on the outer surface by a 3 .mu.m thickness, only about 0.5 .mu.m thickness of nickel-plating is applied on the inner surface. Therefore, due to the poor contact of the inner surface with a positive electrode compound, the contact resistance is raised, as a result the short-circuit current decreases and the performance of an alkaline dry cell falls after a long term storage, furthermore generation of hydrogen gas increases.